Volume 18, Issue 11
Currently known as: Angewandte Chemie International Edition
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908091
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908092
Prof. Dr. Armin de Meijere
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908093
As a small ring with “double bond” character the first member of the cycloalkane series occupies a special position. In recent years increasing use has been made of the special properties of cyclopropanes in developing new synthons (ECO2C(CH3)3).
Prof. Dr. Martin Klessinger and Prof. Dr. Paul Rademacher
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908261
The study of a molecule is usually incomplete if no account is taken of its conformation. Conformational analysis by PE spectroscopy complements conventional methods in case where orbital interactions depend upon the dihedral angle. Hydrazines and biphenyls are prominent examples.
Prof. Dr. Shinji Murai and Prof. Dr. Noboru Sonoda
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908371
“Oxo synthesis with hydrosilane instead of H2” would be one fitting description of the novel reactions with the reagent R3SiH/CO. It functionalizes olefins, cleaves cyclic ethers, inserts into aldehydes RCHO [to give (1)] and permits further promising reactions. CO2(CO)8 is the preferred catalyst.
Prof. Dr. Roger Acher
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908461
Transport of the peptide hormones oxytocin and vasopressin from the hypothalamus to the hypophysial posterior lobe involves the neurophysins, which are proteins made up of ca. 95 amino acid residues. Biosynthesis and transformation of secretory proteins (pro- and prepro-proteins) are gradually being unraveled by present-day research.
Prof. Dr. Henri Brunner, Dr. Joachim Wachter, Prof. Dr. Ivan Bernal and Michael Creswick
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908611
Molybdenum serves as spiro-atom in the complex (3) formed from (1), R CH3, and PhMgBr in the molar ratio of 1:2. One of the two CO groups is transformed into C,O-coordinated benzaldehyde. Ring contraction (1) (2) is already known.
Dipl.-Chem. Werner Benson and Prof. Dr. Ekkehard Winterfeldt
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908621
Stereoconvergence is the aim of economic syntheses of natural products. Tedious saparation of the geissoschizine intermediate (3) from the by-product (1), which arises because of steric interactions between R and CH3, is avoided by hydrolyzing and cyclizing the mixture to the single dilactam (2) with trifluoroacetic anhydride. Regioselective ring opening leads only to (3).
Prof. Dr. Ulrich Schöllkopf, Dr. Wolfgang Hartwig and Ulrich Groth
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908631
Preparatively valuable asymmetric amino acid syntheses must be simple to carry out, give yields of >90%, and, where appropriate, permit recovery of the chiral auxiliary agent. These demands are met by the new synthesis via cyclo-(L-Ala-L-Ala).
Dr. Corrado Berti and Prof. Dr. M. John Perkins
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908641
A new oxidizing agent having remarkable properties has been found in the readily accessible chiral radical (1). It preferentially oxidizes one enantiomer of the test substances D, L-benzil and D, L-benzion, so thet the other enentiomer accumulates. The reactivity and enantioselectivity of (1) should be enhanced by other substituents.
Prof. Dr. Helmut Werner and Dipl.-Chem. Oswald Kolb
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908651
Use of CSSe as a source of CS should facilitate the synthesis of thiocarbonylmetal complexes or actually make it possible in some cases. The first examples are (1) and the compound C5H5(PMe3)Rh(CS) obtained from the corresponding ethylene complex.
Dr. Andreas Heumann, Dipl.-Chem. Marius Reglier and Prof. Dr. Bernard Waegell
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908661
Substituted bi- and polycyclic compounds are accessible from diolefins such as (1), (3), and (5) by reaction with PdCL2 as catalyst in the presence of CuCL2/HOAc/NaOAc. The yields of reactions (3) (4) (77%) and (5) (4) (40%) suggest that (3) has the “correct” stereochemistry for ring closure.
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908671
An insight into the course of the Pd-catalyzed oxidation of diolefins is provided by reaction of 5-methylenecyclooctene (1) with PdCl2/CuCl2/HOAc/NaOAc to give the bicyclic compounds (2) to (5). In benzene, the diolefin (1) reacts with Pd(PhCN)2Cl2 to form the isolable σ-π complex (6) which cyclizes in hitherto unexplained manner to compounds (2) to (5).
Prof. Dr. Hans Gotthardt and Dipl.-Chem. Wolfgang Lenz
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908681
Asymmetric reactions giving products of high enantiomeric purity are of topical interest in synthetic chemistry. An example is the addition of ()-menthyl phenylglyoxylate (1) to dimethylbutene. The product consists of 76.3% of one diastereomer and 23.7% of the other. i.e. its enantiomeric purity is 53% (R()-C10H19).
Priv.-Doz. Dr. Lutz Fitjer and Detlef Wehle
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908682
Production of coronanes of type (1) by a cascade of rearrangements does not appear impossible: a cascade of cyclopropylmethyl-cyclobutyl rearrangements could be initiated in the case of (3). Depending upon the conditions, it gives (4) or (5) and proceeds via four intermediates (GC analysis).
Prof. Dr. Michael Hanack and Dipl.-Chem. Ulrich Michel
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908701
The first solvolytically generated phenyl cation owes its formation to a trick: cyclization and solvolysis of (1) are performed in one step. No phenyl compounds of any kind could be solvolyzed to phenyl cations.
Prof. Dr. Ernst Otto Fischer, Dr. Helmut Fischer, Dr. Ulrich Schubert and Dr. Richard B. A. Pardy
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908711
Fresh light is thrown upon the rearrangements of carbene complexes into carbyne complexes by the spontaneous reaction (1) (2). It is quantitative at room temperature, does not involve an ionic mechanism and refutes the idea that the migrating heteroatom X in (CO)5CrC(NEt2)X must have a lone pair.
Prof. Dr. Karl-Dietrich Gundermann and Dipl.-Chem. Paul-Josef Hnida
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908721
Studies on the extent of possible substitution of cyclobutane led to surprising results. (1), R alkyl, aryl, is known to arise by spontaneous dimerization of acrylonitriles whereas the analogous aldehyde (3) can only be detected by formation of the “Diels-Alder dimer” (4), RCH3 (via methylthioacrolein). (2) was not isolated; its product with iPrNH2 decomposes only at 130°C.
Prof. Dr. Rolf Appel, Dipl.-Chem. Volker Barth, Dr. Mechthild Halstenberg, Prof. Dr. Gottfried Huttner and Dipl.-Chem. Joachim von Seyerl
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908722
Tetraphosphabicyclohexanes were hitherto unknown. The first example to be characterized by X-ray methods is (1), the product of reaction between phosgene and PhP(SiMe3)2. Stereoscopic drawings clearly show the pronounced twisting in the molecule.
Prof. Dr. Rolf Appel, Dipl.-Chem. Volker Barth, Dr. Fritz Knoll and Dr. Ingo Ruppert
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908731
PhPCRPPhPPhCRPPh, RNPhSiMe3, exhibits degenerate Cope rearrangement and configurational isomerism. The clear analogy between the reactions of this methylenephosphane and corresponding alkenes shows that the PC bond of this compound hardly has the ylidic character of methylenephosphoranes.
Prof. Dr. F. Albert Cotton, Dr. William H. Ilsley and Dr. Wolfgang Kaim
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908741
“Normal” and “supershort” CrCr quadruple bonds have been found in complexes. What decides whether the interatomic distance is ca. 2.2–2.5 or < 1.9 Å? The new complex (1) confirms the proposition that axial legands–coordinated solvent molecules in this case–considerably lengthen the bond.
Chem. techn. Manfred Stähle and Prof. Dr. Manfred Schlosser
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908751
A one-pot furan synthesis utilizes the double lithiation of alkynyl tetrahydropyranyl ethers. These reactions are facilitated by the acetal group.
Prof. Dr. Hans Jürgen Bestmann, Dipl.-Chem. Kurt Roth, Dr. Eberhard Wilhelm, Dr. Reinhild Böhme and Prof. Dr. Hans Burzlaff
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908761
The postulated ligand shift process (3) (4) in the Wittig reaction is proved indirectly by the structure and behavior of the primary adduct from a cyclic phosphorus ylide and fluorenone. This primary adduct is too rigid to rearrange to (4).
Prof. Dr. Marianne Baudler and Dipl.-Chem. Dietrich Habermann
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908771
The first three-membered rings to contain 4th row elements are the phosphadiarsiranes (1) and (2) which prepared as shown below. (2) is stable at room temperature. Both compounds are formed as diastereomers; the isomer having trans tert-butyl groups is the more stable.
Prof. Dr. Kurt Heyns, Dipl.-Chem. Siyka Röper, Dr. Harald Röper and Dipl.-Chem. Bernd Meyer
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908781
Nitrosamines in foods are notorious as carcinogens. Sugar amino acids can also form N-nitroso derivatives with nitrite, possibly during the processing of certain foods or in the stomach. The first compounds of this kind have now been synthesized.
Dr. Ingo Ruppert
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908801
Use of fluorine as fluorinating agent permits the first transformation of sulfoxides (1) into the title compounds (2) under mild conditions in the liquid phase. The formation of an oxo cation from (2) with a new fluoroorgano periphery (R aryl) is remarkable.
Univ.-Doz. Dr. Gerd Kaupp and Heinz-Willi Grüter
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908811
The control of photochemical reactions by polar substituents is of value for preparative applications. For example, anthracene (1a) reacts with butadiene to give the [4+2]- (2a) and the [4+4] adduct (3a) in the ratio of 20:1. The carbonitrile (1b), on the other hand, leads to (2b), (3b), and (4) (secondary product of a (3b)-isomer) in the ratio of 1:3.2:13.3. The polar substituent thus suppresses the [4 + 2] reaction (a: X H; b: X CN).
Dr. Christoph Achenbach, Dr. Rolf Ziskoven, Dr. Ferdinand Koehler, Dipl.-Chem. Ute Bahr and Dr. Hans-Rolf Schulten
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908821
The pharmacokinetics of the poisonous element thallium have been examined directly by field desorption mass spectrometry from very small tissue samples. After oral administration of 160 mg/kg to mice, concentrations of 10−4 mol/1 were found in organs. While the teratogenic dose 50% is lower than the lethal dose 50% by a factor of 40, some 12.5% of fetal malformations still occur at 1/1000 of the lethal dose.
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908841
Heimo J. Keller
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908842
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908843
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197908851